Classified cassettes are compatible with Shimano or SRAM 11 or 12 speed rear derailleurs, and Campagnolo 11 and 13 speed rear derailleurs, preferably with a clutch. Make sure the maximum sprocket capacity of your rear derailleur fits the chosen Classified cassette. By making use of a separate shift button, both mechanical and electronic rear derailleurs are compatible with a Classified cassette.
For the most recent overview of groupset compatibility you can check our compatibility chart.